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951.
A DNA fragment containing the entire coding sequence of nitrilase gene was amplified from Rhodococcus rhodochrous tg1-A6 with high nitrilase activity using PCR and sequenced. The open reading frame of the nitrilase gene contains 1,101 base
pairs, which encodes a putative polypeptide of 366 amino acid residues. The nitrilase gene was cloned into an expression vector
pET-28a and expressed in an Escherichia coli strain BL21(DE3). The enzymatic activity of nitrilase, which converts various nitriles to the corresponding carboxylic acids,
was detected to reach 24.5 U/ml at 9 h in the recombinant bacteria. 相似文献
952.
Jian-Ping Zou Sheng-Lian Luo Ming-Jun Li Xin-Hua Tang Qiu-Ju Xing Qiang Peng Guo-Cong Guo 《Polyhedron》2010
A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C7H2NO5)·3H2O]n·nH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)3·4H2O]n·2nH2O (5) and [Ce(C7H2NO5)·1.5H2O]n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (44) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied. 相似文献
953.
Xiaoteng Luo Jingjing Xu John Barford I-Ming Hsing 《Electrochemistry communications》2010,12(4):531-534
This work reports a novel electrochemical PCR detection platform using magnetic particles as a separation tool. A redox-active intercalator, anthraquinonemonosulfonic acid (AQMS), was firstly intercalated into biotin labeled PCR amplicons, and the resulting complex was then captured by streptavidin-coated magnetic particles (MPs) to form AQMS–DNA–MP conjugates. Subsequently, these conjugates were attracted to the bottom of the tube and separated from the solution by applying an external magnetic field, resulting in a significant reduction of the concentration of solution AQMS. The concentration changes of solution AQMS, which reflect the presence and quantity of PCR amplicons, were monitored by differential pulse voltammetry (DPV) on a chip electrode. PCR cycle number-dependent as well as the initial template DNA concentration-dependent performances were investigated. This electrochemistry based PCR detection platform is simple, convenient and inexpensive, and may have potential applications for practical sample monitoring. 相似文献
954.
Xiaomei Cao Yanhong Xu Liqiang Luo Yaping Ding Ying Zhang 《Journal of Solid State Electrochemistry》2010,14(5):829-834
A glassy carbon electrode (GCE) modified with the film composed of chitosan incorporating cetylpyridine bromide is constructed
and used to determine uric acid (UA) and ascorbic acid (AA) by differential pulse voltammetry (DPV). This modified electrode
shows efficient electrocatalytic activity and fairly selective separation for oxidation of AA and UA in mixture solution.
UA is catalyzed by this modified electrode in phosphate buffer solution (pH 4.0) with a decrease of 80 mV, while AA is catalyzed
with a decrease of 200 mV in overpotential compared to GCE, and the peak separation of oxidation between AA and UA is 260
mV, which is large enough to allow the determination of one in presence of the other. Under the optimum conditions, the anodic
peak currents (I
pa) of DPV are proportional to the concentration of UA in the range of 2.0 × 10−6 to 6.0 × 10−4 M, with the detection limit of 5.0 × 10−7 M at a signal-to-noise ratio of 3 (S/N = 3) and to that of AA in the range of 4.0 × 10−6 to 1.0 × 10−3 M, with the detection limit of 8.0 × 10−7 M (S/N = 3). 相似文献
955.
956.
Li-Qiang Luo Qiu-Xia Li Ya-Ping Ding Ying Zhang Xia Shen 《Journal of Solid State Electrochemistry》2010,14(7):1311-1316
A glassy carbon electrode (GCE) modified with docosyltrimethylammonium chloride (DCTMACl) is used for simultaneous determination of dopamine (DA) and ascorbic acid (AA) using differential pulse voltammetry (DPV) technique in 0.10 mol·L?1 phosphate buffer solution of pH 5.0. The cationic surfactant DCTMACl modified film has a positive charge. DA exists as the positively charged species, whereas AA is the negatively charged one in the solution. Thus, at DCTMACl film-modified GCE, the oxidation peak potential of AA shifts toward less negative potential and the peak current of AA increases a little, while the oxidation peak potential of DA shifts toward more positive potential and peak current decreases greatly in comparison with that on bare electrode. The two anodic peaks are separated around 200 mV. Under optimal conditions, the catalytic peak currents obtained from DPV increase linearly with concentrations of DA and AA in the ranges of 1.0?×?10?5 to 1.0?×?10?3?mol·L?1. This electrode has good reproducibility, high stability in its voltammetric response, and low detection limit (micromolar) for both AA and DA. The modified electrode has been applied to the determination of DA and AA in injection. 相似文献
957.
H-shaped bridged oligothiophenes HT-1 and HT-2 were synthesized by two different approaches. Different from normal oligothiophenes, HT-1 and HT-2 showed low band gaps and amphoteric redox behaviors due to intramolecular charge transfer, which is further supported by time-dependent DFT calculations. 相似文献
958.
Yuqin Yao Zhihui Cheng Haoyu Ye Yongmei Xie Jing He Minghai Tang Tao Shen Jiangman Wang Yan Zhou Zejun Lu Feng Luo Lijuan Chen Luoting Yu Jin‐Liang Yang Aihua Peng Yuquan Wei 《Journal of separation science》2010,33(9):1331-1337
Ansamitocin P‐3 is a potent anti‐tumor maytansinoid found in Actinosynnema pretiosum. However, due to the complexity of the fermentation broth of Actinomycete, how to effectively separate ansamitocin P‐3 is still a challenge. In this study, both analytical and preparative high‐performance counter‐current chromatography were successfully used to separate and purify ansamitocin P‐3 from fermentation broth. A total of 28.8 mg ansamitocin P‐3 with purity of 98.4% was separated from 160 mg crude sample of fermentation broth in less than 80 min with the two‐phase solvent system of hexane–ethyl acetate–methanol–water (0.6:1:0.6:1, v/v/v/v). The purity and structural identification were determined by HPLC, 1H NMR, 13C NMR and mass spectroscopy. 相似文献
959.
Chun Lin Wenjun Luo Sheng Zhang Zhenbin Zhang Weiguang Zhang Shengrun Zheng Jun Fan Weishan Li Qing Qin Ziyuan Guo 《Journal of separation science》2010,33(11):1558-1562
Two types of chiral stationary phases for HPLC based on π‐acidic or π‐basic perphenylcarbamoylated β‐CDs were synthesized. The relative structural features of the two effective chiral selectors are discussed and compared in both normal‐phase and RP modes. In addition, the nature and concentration of alcoholic modifiers were varied for optimal separation in normal phase and the structural variation of the analytes was also examined. The results showed that hydrogen bonding, steric effect and π‐acidic–π‐basic interaction contributed greatly to enantioseparation. Upon comparison, some of the differences in the separation behavior of the two types of chiral stationary phases might be due to the π‐acidic or π‐basic phenylcarbamate groups. 相似文献
960.
Limin Han Guangbin Zhang Ning Zhu Ruijun Xie Quanling Suo Meihua Luo Linhong Weng 《Journal of Cluster Science》2010,21(4):789-801
Two novel bimetallic complexes, [Cr(CO)3(η
6-C6H5)–C≡C–C6H4–Fc] (Fc = C5H5FeC5H4] (1) and [Cr(CO)3(η
6-C6H5)–C ≡ C–Fc–C(CH3)2–Fc] (3), were synthesized by the Sonogashira coupling reaction. By using of (1) and (3) as ligands to react with Co2(CO)8, two others novel polymetallic complexes, [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}–C6H4–Fc] (2) and [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}Fc–C(CH3)2–Fc] (4) were obtained. Four carbonyl complexes were characterized by elemental analysis, FT-IR, NMR and MS. The molecular structures
of complexes (1), (2) and (4) were determined by single crystal X-ray diffraction. The interactions among the ferrocenyl,
Cr(CO)3 and Co2(CO)6-η
2-μ
2-C≡C– units were investigated by cyclic voltammetry. 相似文献